Data Sufficiency - Q1 - Is P the youngest among P, Q, R, S?

Q.

Is P the youngest among P, Q, R and S?

I. There is no person younger than P
II. There are at least two persons older than P


A.

To start off, understanding the word 'youngest' is very important. Youngest is a superlative, hence let us look at the definition of a superlative.

http://en.wikipedia.org/wiki/Superlative

I am calling out the part I need here,
"In grammar, the superlative is the form of an adverb or adjective that expresses a degree of the adverb or adjective being used that is greater than any other possible degree of the given descriptor"

This means that P is the youngest ONLY IF P is younger than Q, R and S. The inequality "younger than" has to be strictly an inequality.

Let us consider the possibilities for Statement I alone, Statement II alone and Statement I and II together.

Possible solutions for Statement I alone, "There is no person younger than P"
P = 10, Q = 20, R = 30, S = 40  --> P is the youngest
P = 10, Q = 10, R = 30, S = 40  --> P is not the youngest since P is not younger than Q

Hence the question "Is P the youngest?" cannot be answered with Statement I alone.

Possible solutions for Statement II alone, "There are at least two persons older than P"
P = 10, Q = 20, R = 30, S = 40  --> P is the youngest
P = 20, Q = 10, R = 30, S = 40  --> P is not the youngest

Hence the question "Is P the youngest?" cannot be answered with Statement II alone.

Possible solutions for Statement I and II together,
P = 10, Q = 20, R = 30, S = 40  --> P is the youngest
P = 10, Q = 10, R = 30, S = 40  --> P is not the youngest since P is not younger than Q

Hence the question "Is P the youngest?" cannot be answered with Statement I and II together.


-Aptitude Plus